Cross drilled discs

[allankelly1]

Hi all

Hope you are all well

Bike is off the road while I progress the rear disc conversion but wondered if anybody has ever cross drilled their discs?

I know the golden rules like the hole pattern most cover the whole disc face etc but does it make any different or is it just a style thing

As thinking if I am bored once the rear disc project is completed I may cross drill both the rear disc and the twin disc set up before spring time



Any thoughts

Best wishes Al


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[taysidedragon]

Manufactured and modified drilled discs have a lot of different hole spacings and patterns.
I don't think it matters too much as long as you don't weaken the disc.

[allankelly1]

Yes there are plenty of drill patterns on the web and as the discs are stainless they are less prone to cracking

Like I said. The pattern must cover the pad swept area and the hole only slightly bigger than the the disc thickness

Think it time to cad something up

Also when I did the rear disc conversion I bought a spare disc so got something to practice on as recon I will need to get some carbide drills due to the disc being stainless


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[MrDavo]

As a student I used to regularly drop in to Sports Motorcycles in Manchester to lust at the bikes there.

I've never seen it reported, and the bike certainly doesn't have them now, but I saw with my own eyes that the original NCR Ducati that Mike Hailwood rode in his TT comeback had radially drilled discs, ie the holes went from the edge to the inside of the disc. They were beautifully done, with countersunk holes and done at an angle making an airscoop effect, no doubt saving unsprung weight as well as cooling. Proper 'works' bike stuff.

I've never seen this in any article or photo of that bike, and no doubt when they wore out or warped they got replaced with ordinary discs, I've seen the bike a couple of times and there is no sign. However I know what I saw, so just recording this for the reference of google and internet could be useful to someone. I wonder if the current owner knows?

[allankelly1]

Lovely


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[Laverdaroo]

Nicely done sir, terribly satisfying isn't it

[allankelly1]

Yes very nice especially on a spoked wheel.

but my own work as found pic on web but love the design so thinking by of copying onto my front and back disc set up


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[Laverdaroo]

I did mine on the kitchen table, the hardest part of the whole process was not getting toast crumbs under the paper

Loads has been written on the amount of drill bits people get through but I had absolutely no issue at all.

My pedestal drill is with the large in the container so had to improvise but worked a treat.

I calculated the curb as being exactly a 4” masking tape reel with 1/4” of tape still on it

Worked pretty good and looks ace. I’ll be doing the 550 the same when I get that far forward, just started the carbs




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[Laverdaroo]

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[allankelly1]

Nice

Once I have sorted my back out I have a nice dividing head at work so should be a simple operation once I have worked out pitch and pattern


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[Laverdaroo]

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[allankelly1]

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[Laverdaroo]

I hate spell check! It’s always pissed!


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[allankelly1]

Yes I hate predicting text too

But definitely drilling as love that look

Thanks for the encouragement

Another project to do on the old girl but better sort out that rear disc mod first but recon I am almost there now I have sorted a disc locker design




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[Laverdaroo]

Yeah, I saw that the other nigh, it looks bloody splendid when you poke it all together and the brake pedal too and on the bike. That's one pretty bike with some ace mods on. When I get my new workshop in the new house I'm hoping to have a bit more space so the lathe will be out...............finaly! Its an old sh**ter but its lovely to work on. 
Can't wait to put some ideas into practice and watching the threads you put up have proper fired me up. Your work puts mine in the amateur category but I love doing it all the same. I got notification that the steel-dragon air box has been shipped from the states so I'm about three nights in the shed away from a finished 400!

Keep up the photo posts mate, I'm loving ths one its brilliant!

Forgot to mention,
My eldest nephew saw that piccy of the your 400 under he streetlamp you posted a while ago and on the back of that he's booked his test!! He was blown away by it, well done Allan, another one in the club